The mechanisms by which extracellular macromolecules, from Streptococcus mutans, are involved in the formation of cariogenic dental plaque are under investigation. Glucosyltransferases, fructosyltransferases, lipoteichoic acids, and dextranases have been partially characterized biochemically and immunologically. Interactions of these molecules with hydroxyapatite, enamel, components of dental plaque and/or saliva and antisera, as well as the effects of antiplaque agents on these interactions are being investigated. Macromolecule preparations found immunogenic in rats and/or monkeys are being tested as vaccines against dental caries; antibody classes are being assayed. These studies are designed to gain insight into the biochemical and immunological aspects of dental caries which will lead to a rational approach for the control of this disease. BIBLIOGRAPHIC REFERENCES: Ciardi, J.E., Rolla, G., Bowen, W.H. and Reilly, J.A. Adsorption of Streptococcus mutans lipoteichoic acid to hydroxyapatite. Scand. J. Dent. Res. In press, 1977. Ciardi, J.E., Beaman, A.J. and Wittenberger, C.L. Purification, resolution and interaction of the glucosyltransferases of Streptococcus mutans, Strain 6715. Infection and Immunity. In press, 1977.